Fire detecting cable



June 6, 1939. Q R, WHEELER 2,161,395

FIRE DETECTING CABLE Filed Oct. 13, 1937 INVENTOR ATTORNEYS Patented June 6, 1939 UNITED STATES PATIENT OFFICE 1Clailn.

This invention relates to re detecting cables for electric circuits, and its general object is to provide a cable that includes material which is readily fusible under the action of heat caused by fire in close proximity to the cable, so as to close a normally open circuit of suitable signalling means, such as a bell, buzzer, light, etc. to indicate the nre at a place remote therefrom.

A further object is to provide a nre detecting cable that is freely bendable, can be readily handled, rolled and-folded without damage thereto, and can be installed and associated with fixtures and the like in the same manner as cables now in general use, yet is capable of performing its intended function in providing utmost security and protection against material loss by re.

Another object is to provide a fire detecting cable, that is simple in construction, inexpensive to manufacture, and extremely efilcient in use and service.

'I'his invention also consists in certain other features of construction and in the combination and arrangement of the several parts, to be hereinafter fully described, illustrated in the accompanying drawing and specifically pointed out in the appended claim.

In describing the invention in detail, reference will be had to the accompanying drawing wherein like characters denote like or corresponding parts throughout the several views, and in which:

Figure 1 is a view partly in section illustrating one form of cable which forms the subject matter of the present invention.

Figure 2 isa sectional view taken approximately on line 2--2 of Figure l, looking in the direction of the arrows.

Figure 3 is a view partly in section of a modi- :lied form of cable.

Figure 4 is a sectional view taken approximately on line 4-4 of Figure 3, looking in the direction of the arrows.

Figure 5 is a view partly in section of another modined form.

Figure 6 is a sectional view taken approximate- 1y on une s-s of Figure 5,1o0king1n the direction of the arrows.

Referring to the drawing in detail and particularly to Figures l and 2, it will be noted that the cable includes a pair ofwires or conductors I, each of which is provided with a coating 2 in the form of a sleeve or tubing and the sleeves are preferably solid, for engagement with and about the wires which are disposed centrally therein, as best shown in Figure 2. The sleeves are made (Cl. ZIN-143) from material which will readily fuse under the action of heat, such as metal alloy generally used for that purpose.

The sleeve incased wires are held in spaced parallel relation with respect to each other by blocks 3 disposed in equi-distantly spaced relation, and the blocks are formed from rubber or other suitable insulating material, with concaved recesses in the opposite faces thereof to act as seats for the sleeves, as best shown in Figure 2. Surrounding the sleeves and holding them seated on the blocks, is a layer l of insulating material that is preferably in the form of tape of rubber or the like that is spirally wound about the sleeves, as shown in Figure 1, and surrounding the layer l is a layer 5 which is also in the form of tape spirally wound about the layer I, but the layer 5 is of metal of any flexible type that may be freely wound in the manner shown and it will be noted that both of the layers provided by the tape are wound whereby the edges of the tape are disposed in engagement to provide a complete closure.

'I'he layer l may be perforated, but in any event an outer covering 6 of fabric material surrounds the layer 5, to complete the cable. It will be obvious that the perforations tend to allow heat to more readily pass within the cable and contact the fusible sleeves 2.

In the modified form of Figures 3 and 4, it will be noted that the cable is substantially similar to that shown in Figures 1A and 2, but the fusible sleeves or tubings which are indicated by the reference numeral 1 are separated by strips 8,instead of the blocks 3, the strips being spirally wound about the sleeves with the convolutions thereof disposed in spaced relation, and the strips which are of suitable insulating material such as rubber, are relatively thick, to space the sleeves a considerable distance apart.

Surrounding the spirally wound strips 8 is a layer 9 similar to the layer 5, in that the layer 9 is in the form of tape spirally wound about the strips 8 and the tape is likewise of metal and may be perforated. An outer covering or casing i is disposed about the layer 9, and the cover i0 is of fabric material as will be apparent.

In the form of Figures and 6, the fusible sleeves or tubings which are indicated by the reference numeral Il are held in spaced relation by inner and outer layers of material in the form of strips, each layer being made up of companion strips and the inner companion strips which are indicated by the reference numeral I2 are of insulating material such as rubber, whilethe outer companion strips I3 are of metal, which is of course freely bendable, so that the cable can be handled, rolled and folded.

'Ihe strips I2 have their outer portions curved as at I4 longitudinally throughout their length, with the edges thereof disposed in contacting engagement, so that the curved portions provide vchannels I5 to receive and hold the sleeves in spaced relation with respect to each other, and the intermediate portions of the strips I2 are likewise spaced to provide a chamber or passageway I6 for the melted metal when the sleeves become fused and as will be apparent upon inspection of Figure 6. The strips I3 are of the same shape as the strips I2, for fitting association therewith, and surrounding the strips I3 is a cover or casing I1 of fabric material, to complete the cable of this form.

In each form of the invention, it will be obvious that the sleeves act as conductors, in that the wires extend through the same and are disposed in contacting engagement therewith, consequently when the sleeves become fused, the metal thereof will bridge the space between the same, and thereby close the circuit.

It is thought from the foregoing description that the advantages and novel features of the invention will be readily apparent.

It is to be understood that changes may be made in the construction and in the combination and arrangement of the several parts, provided that such changes fall within the scope of the appended claim.

What I claim is:

A fire detecting cable comprising conductor wires, a tubular sleeve incasing each of the wires and formed from easily fusible material, equidistantly spaced blocks of insulating material between the sleeves for spacing the same a substantially great distance apart and having concaved recesses in the opposite faces thereof providing seats fitting and receiving the sleeves therein, a layer of tape of insulating material spirally wound about the sleeves, a layer of tape of flexible metallic material spirally wound about the rst layer and each layer being wound with its edges disposed in engagement, the layer of metallic tape having perforations therein for the passage of heat therethrough, and an outer covering of fabric material surrounding the layer of metallic tape.

DOCK R. WHEELER.. 

